When German and Russian Biotar type 58mm lenses are used on a Sony a6100 camera with an APS-C sensor, a crop-factor of 1.5 applies. That makes the field of view almost the same as a 85mm portrait lens used on a 35mm equivalent full-frame camera like the Sony a7ii.
In my opinion, the following photos quite nicely answer the following question: Are the German and Russian Biotar type lenses of any use when adapted to an APS-C mirrorless camera body?
When you click on a photo in the galleries, following buttons will allow you to select some features, including a slideshow or to view in original size of 24 mega-pixel resolution:
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Photos exclusively shot with the Carl Zeiss Biotar 58mm f2 lens on a Sony a6100 camera with APS-C sensor
For the following photographs shot at a scenic golf course south of Munich, only the Carl Zeiss Biotar 58mm f2 lens was used on a Sony a6100 camera with a small APS-C sensor. I expected the EUR 60 Russian copy Helios 44M-4 to deliver the same results. Thanks to talented golfer Rohan and Matthias for posing as models.
Comparison: photos of German and Russian Biotar 58mm f2 lenses on a Sony a7ii camera with full-frame sensor and a Sony a6100 camera with APS-C sensor
Let’s have a look at some photographs of classic cars. These were on show at a former Echelon and NSA satellite tracking station compound in Bad Aibling, southern Bavaria, on the 31st of July, 2021.
These photos demonstrate that the Russian Helios 44M-4 58mm f2 lens for EUR 60 delivers the same image quality and bokeh as the Carl Zeiss Biotar 58mm f2 lens for EUR 250, and both lenses performed well when shooting them on a Sony a6100 camera with a small APS-C sensor.
Beyond their swirly bokeh, what makes the Carl Zeiss Biotar 58mm f2 lens and the Russian copy so special?
Answer: Their wet-on-wet bokeh.
The term “bokeh” has been defined as the way the lens renders out-of-focus points of light. See more information about bokeh here: https://wikipedia.org/Bokeh
Although bokeh quality is a matter of individual taste, Rick Denney gives some good examples of which kind of bokehs are distracting, neutral or pleasing: http://www.rickdenney.com
Despite the swirly bokeh of the tested German and Russian Biotar type lenses, which show only under certain conditions, the way both lenses render objects out of focus corresponds to the wet-on-wet technique for watercolor paintings, i.e. adding wet paint onto wet paper, allowing the added pigment to spread out unhindered.
Take a look at some crops of the photos shown in above galleries. In my opinion, the “characterful” wet-on-wet bokeh is the real star, not the object in focus:
Read more about the origin and history of the Carl Zeiss Biotar and Helios 44M-44 58mm f2 classic lenses here
The image quality and bokeh of the Carl Zeiss Biotar 58mm and Helios 44M-4 58mm classic lenses barely differ. The image rendering and bokeh of these lenses are different, depending on whether they are adapted to a Sony a7ii full-frame camera or to a Sony a6100 APS-C camera (the sensor size of an APS-C camera is only 2/3 of a full-frame sensor). Nevertheless, the image rendering and bokeh difference is much less than expected if the distances to the object and background are increased compared to a full-frame camera.
Both classic Biotar type lenses proved able to deliver good images, with a beautiful image rendering character and bokeh when adapted to the Sony a6100 APS-C camera. The Russian Helios 44M-4 58mm f2 lens convinced with an excellent price/performance ratio (approx. EUR 60).
Thanks to my friend Randolph for shooting almost all photos with the full-frame Sony a7ii camera, while I was shooting with the Sony a6100 APS-C camera. And thanks to Sergii for lending his Helios 44M-4 lens.
Not all M42-to-Sony-e-mount adapters are compatible with the Carl Zeiss Biotar 58mm f2 lens, as with some adapters the lens cannot be completely turned inside due its large bulge into the adapter. With those incompatible adapters, focus at infinity is lost. If you want to adapt the Carl Zeiss Biotar lens, you are invited to ask for a compatible adapter in the comment section below.
- It might be wiser to use an inexpensive, small and lightweight APS-C camera for EUR 600 with a classic Helios 44M-4 58mm f2 prime lens instead of a EUR 2,000 mirrorless full-frame camera with a plastic-is-fantastic, slow and characterless zoom kit lens, which has an ugly onion ring bokeh.
- The main reasons for a good photo are – as always – motive, lighting and composition. An experienced photographer with an iPhone will take better photos than an amateur with EUR 5,000 worth of camera equipment.
- Never go out shooting in sunlight with Biotar type lenses without both an ND8 neutral density filter to avoid over exposure and a lens hood to avoid lens flares at open aperture.
- Playing with bokeh, creating it, or capturing it can be fun. Find a very informative article about bokeh from B&H here: https://www.bhphotovideo.com